Guide for bonding tapes or films

ABSTRACT

A guide is provided to direct the film or tape into the bonding area of a bonding apparatus. The guide includes first and second curved plates which are affixed to and separated by a spacer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/694,051, filed on Jun. 24, 2005, which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a guide used to direct the film or tape into the bonding area of a bonding apparatus.

2. Summary of Related Art

Polyurethanes (including polyurethaneureas) can be used as adhesives for various substrates, including textile fabrics. Typically, such polyurethanes are either fully formed non-reactive polymers or reactive isocyanate-terminated prepolymers. Typically, such polymers, when fully formed, are either dissolved in a solvent (solvent borne), dispersed in water (water borne), or processed as thermoplastic solid materials (hot melt). These dispersions may be formed into films or tapes which may be bonded to fabric.

Films or tapes used for bonding to fabric must be carefully fed into the bonding apparatus to ensure accurate placement on the substrate. Current commercial bonding apparatus lack the proper equipment to properly feed the tapes or films of the present invention. Thus, it is desirable to provide an improved guide for directing the film or tape into the bonding apparatus.

SUMMARY OF THE INVENTION

One aspect of the present invention provides a device useful as a guide for feeding polyurethane tapes or films into a bonding machine. The guide includes first and second curved plates each having an interior upper surface, an exterior lower surface, and a spacer having a rectangular prism configuration including an upper surface, a lower surface, a length, a width, and a thickness. The second curved plate is placed interior to the first curved plate with the spacer between the first and second plates such that the exterior lower surface of the second curved plate contacts the upper surface of the spacer and the interior upper surface of the first curved plate contacts the lower surface of the spacer and the width of the spacer is less than the width of the first curved plate and less than the width of the second curved plate.

Another aspect of the invention provides a method for feeding a tape to a bonding machine including passing a tape though the guide of some embodiments of the invention to a bonding machine.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described in the following detailed description with reference to the following drawings:

FIG. 1A is a perspective view of one embodiment of the guide of the invention;

FIG. 1B is a side view of one embodiment of the guide of the invention;

FIG. 2 is a top view of one embodiment of the guide of the invention; and

FIG. 3 is a view showing the tip of one embodiment of the guide of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The guide of some embodiments includes a guide including first and second curved plates which are separated by a spacer. The guide permits a polyurethane tape or film to be fed through the guide to a bonding machine such as the SewSystems AT750 bonding machine (commercially available from Sew Systems, Leicester, United Kingdom).

As used herein, the term “mil” refers to one-thousandth of an inch, and the term “microinch” refers to one-millionth of an inch.

As shown in FIGS. 1A and 1B, the first curved plate 1 may be longer than the second curved plate 2. The first 1 and second 2 curved plates are aligned such that one and of the first curved plate is adjacent to an end of the second curved plate which forms the outlet 10 for the tape or film. The guide may be attached to a bonding machine at the mounting location at the opposite end of the guide 15. The spacer is aligned to the side of guide between the first and second curved plates. The first 1 and second 2 curved plates, together with the spacer 20 define the outlet 10 for the tape or film. The spacer may be affixed to the first and second curved plates at one or more locations 14 along the length of the spacer by any means known in the art such as spot-welding.

The guide may include three general regions. The first region 11, has generally a rectangular configuration as shown from the top view of FIG. 2. The first region 11 includes an inlet 5 for accepting the polyurethane film or tape which is shown in FIGS. 1A and 1B. The third region 13 also may have a generally rectangular configuration and includes the outlet 10. The second region 12 is located between the first 11 and third 13 regions and is tapered between the wider width of the first region 11 to the smaller width of the third region 13. The width of the guide allows use for polyurethane tapes of a width from about 0.1 inch to about 1 inch without folding the tape.

The spacer 20 is shown in more detail in FIG. 3. The spacer separates the first and second curved plates and may have any suitable shape such as a rectangular prism configuration. The spacer 20 has an upper surface which is in contact with the exterior lower surface of the second curved plate 2 b and a lower surface which is in contact with the interior upper surface 1 a of the first curved plate. The spacer may be of any suitable thickness to allow a selected polyurethane tape or film to be fed through the guide. For example, the spacer may have a thickness to allow the guide to accept a tape from about 1 mil to about 100 mils in thickness, specifically from about 1 mil to about 50 mils. The thickness of the spacer may be about 250 mils or greater which corresponds to the thickness of the spacer 20.

The first curved plate of the guide, which in use would be closest to the fabric to which a tape or film is to be bonded has upper 1 a and lower 1 b surfaces. The lower surface would be closest to the fabric. These surfaces are also referred to as the interior and exterior surfaces, respectively, to denote the surface interior or exterior to the curve. The upper surface may have a roughness greater than the lower surface. For example the upper surface may have a roughness (RMS) of about 65 μin (microinches) to about 75 μin and the lower surface may be smoother, for example, from about 8 μin to about 12 μin. The first curved plate may have a length from about 3 in (inches) to about 4 in, specifically from about 3.1 in to about 3.3 in and a radius of curvature of at least about 3 in, specifically about 3 in or greater, more specifically of about 5 in or greater.

The second curved plate may have a radius of curvature greater than the radius of curvature of the first curved plate for example, at about 3 in or greater or about 5 in or greater. The length of the second curved plate is shorter than that of the first curved plate. For example the length may be from about 1.0 in to about 1.5 in, specifically from about 1.0 in to about 1.2 in. The roughness of the upper and lower surfaces of the second curved plate may be similar, for example, a roughness (RMS) of about of about 65 μin to about 75 μin. The second curved plate may have a first section 2 c adjacent to the inlet of the guide and second section 2 d adjacent to the outlet of the guide. The first section 2 c may be substantially flat and form an obtuse angle with respect to the second section 2 d which is curved.

A large variety of polyurethane tapes and films are useful with the guide of some embodiments. Examples of suitable tapes and films are disclosed in U.S. Pat. Nos. 4,387,181; 5,270,433; 5,563,208; 6,555,613; and 6,586,523 and U.S. Patent Publication Nos. 2004/001480 A1 and 2003/0220463 A1; and co-pending U.S. application Ser. No. 11/056,067 filed on Feb. 11, 2005; all of which are incorporated herein by reference.

The method of some embodiments includes the use of the guide described hereinabove to feed a polyurethane film or tape into a bonding apparatus to affix the film or tape to fabric.

Smoothness: Root Means Squared (RMS)

Surface texture is a measure of the distance between the peaks and valleys of a surface and typically expressed as a root means squared (RMS) of the value as defined in standard ASME B46.1-2002. A Sheffield Profilometer (commercially available from Avon Gear, Company, Rocheser Hills, Mich.) is a typical instrument for expressing such values.

EXAMPLES

Representative embodiments of the present invention will be described with reference to the following examples that illustrate the principles and practice of the present invention. In these examples:

Comparative Example 1

A fabric was hemmed using a SewSystems AT750 bonding machine (commercially available from Sew Systems, Leicester, United Kingdom). The SewSystems standard chute (part # SS61212/1 Hemmer Chute) was used to hem the edges of a fabric using a polyurethane tape having a thickness of 6 mils. The hemming was unsuccessful as the tape did not travel through the SewSystems chute.

Comparative Example 2

The method from comparative example 1 was used, however the standard SewSystems chute was modified. The chute was roughened using 90 grit aluminum oxide blasting for 30 seconds to give a surface roughness of 65-75 RMS. The tape did not pass though the chute smoothly and the hemming was unsuccessful.

Inventive Example 3

In this example, the SewSystems bonding machine in combination with the inventive guide shown in FIG. 1 were used in combination with a polyurethane tape having a thickness of 6 mils to successfully hem a fabric at a temperature of 180 C.

While the present invention has been described in an illustrative manner, it should be understood that the terminology used is intended to be in a nature of words or description rather than of limitation. Furthermore, while the present invention has been described in terms of several illustrative embodiments, it is to be appreciated that those skilled in the art will readily apply these teachings to other possible variations of the invention. 

1. A device comprising: (a) a first curved plate comprising an interior upper surface, an exterior lower surface and a width; (b) at least one spacer comprising a rectangular prism having an upper surface, a lower surface, a length, a width, and a thickness; and (c) a second curved plate comprising an interior upper surface, an exterior lower surface and a width; wherein said second curved plate is placed interior to said first curved plate; the exterior lower surface of said second curved plate contacts said upper surface of said spacer; the interior upper surface of said first curved plate contacts said lower surface of said spacer; and the width of said spacer is less than the width of said first curved plate and less than the width of said second curved plate.
 2. The device of claim 1 wherein said first curved plate is longer than said second curved plate.
 3. The device of claim 2, wherein said first curved plate and said second curved plate are aligned such that one end of said first curved plate is adjacent to an end of said second curved plate and the other end comprises a mounting location.
 4. The device of claim 1, wherein said first curved plate and said second curved plate comprise a guide having a first region comprising an inlet for accepting a polyurethane tape; a second tapered region; and a third region comprising an outlet for said tape; wherein said first region has a greater width than said second region.
 5. The device of claim 4, wherein said first curved plate and said second curved plate are aligned at the end of said outlet.
 6. The device of claim 4, wherein said second curved plate comprises a first section adjacent to said inlet and a second section adjacent to said outlet wherein said first section is substantially flat and forms an obtuse angle with respect to the second section of said second curved plate.
 7. The device of claim 1, wherein said first curved plate has a radius of curvature of about three inches or greater.
 8. The device of claim 1, wherein said first curved plate has a radius of curvature of about five inches or greater.
 9. The device of claim 1, wherein said second curved plate has a radius of curvature of about three inches or greater.
 10. The device of claim 1, wherein said second curved plate has a radius of curvature of about five inches or greater.
 11. The device of claim 1, wherein said first curved plate has a radius of curvature greater than a radii of curvature of said second curved plate.
 12. The device of claim 4, wherein said spacer has a thickness sufficient to allow said guide to accept a tape from about 1 mils to about 50 mils.
 13. The device of claim 1, wherein said upper surface of said first curved plate has a roughness of about 65 microinches to about 75 microinches, and is greater than the roughness of said lower surface of said first curved plate which is from about 8 microinches to about 12 microinches.
 14. The device of claim 1, wherein said upper surface of said second curved plate has a roughness of about 65 microinches to about 75 microinches, and said lower surface of said second curved plate has a roughness of about 65 microinches to about 75 microinches.
 15. The device of claim 1, wherein said first curved plate has a length from about 3.1 inches to about 3.3 inches.
 16. The device of claim 1, wherein said second curved plate has a length from about 1.0 inches to about 1.2 inches.
 17. A method of feeding a tape to a bonding machine comprising passing said tape through a guide to said bonding machine wherein said guide comprises: (a) a first curved plate comprising an interior upper surface, an exterior lower surface and a width; (b) at least one spacer comprising a rectangular prism having an upper surface, a lower surface, a length, a width, and a thickness; and (c) a second curved plate comprising an interior upper surface, an exterior lower surface and a width; wherein said second curved plate is placed interior to said first curved plate; the exterior lower surface of said second curved plate contacts said upper surface of said spacer; the interior upper surface of said first curved plate contacts said lower surface of said spacer; and the width of said spacer is less than the width of said first curved plate and less than the width of said second curved plate. 